It is estimated that 85% of graft and fistula failures are predictable, treatable and hence preventable.

Unfortunately, in the real world we live in, resources for monitoring are not currently funded by Medicare, the usual payor for most dialysis services. The units that do invest in monitoring must find the funds to provide monitoring at the expense of other needed services. Procrastination and denial on the part of the patients, combined with the many demands on dialysis providers, and uneven experience also contribute to a failure to catch the failing access before it clots.

So – inevitably – in a dialysis population, a certain number of patients will clot their accesses every day. In the past, this usually meant spending hours in emergency, hours waiting for the surgeon, another and another surgery, and disruption to the personal schedule. Worse yet, the patient could find him or herself with a catheter, and weeks or months of delay until another access is successfully placed and the catheter removed. Fortunately, newer approaches now exist.

Endovascular thrombolysis of dialysis access is an extension of endovascular maintenance of access (see article). It is generally an outpatient procedure performed by Interventional radiologists, qualified surgeons, or Interventional nephrologists.

The procedure can take between 45 minutes and two hours, depending on the severity of the problem and the experience of the operator. In general, 85% of clotted grafts can be rescued without open surgery, and the graft is almost always usable the same day.

First, the clot in the graft must be removed or dissolved by one of several means. I prefer mechanical thrombolysis, which consists of grinding up the clot in the graft and then suctioning it out (think "Roto-rooter"), but some doctors prefer chemical thrombolysis, in which enzymes are dripped into the clot to dissolve it (think "Drano"). Once the clot is dissolved and removed, a small amount of x-ray dye is injected to examine the graft and find the reason for thrombosis.

Although the problem causing thrombosis of the graft is generally narrowing at the venous anastomosis (seen in 90% of clotted grafts), narrowing in the body of the graft due to frequent punctures, narrowing in the central veins due to previous catheters, and narrowing in the arterial inflow of the graft are also frequent problems, and must be corrected to achieve an acceptable result. Failure to recognize and correct all the problems can mean that the patient will return sooner than expected with a reclotted graft.

All narrowings are dilated with balloons inserted through the same small punctures used for the thrombolysis and x-ray examination. If necessary, a stent can also be placed if an acceptable result is not obtained (to prop open a stubborn narrowing), or if the graft ruptures during dilation (to patch the leak from the inside). Finally, the clot in the arterial end is removed, and flow restarted. When the result is judged acceptable, the punctures are sutured, and the patient can return to dialysis immediately with a usable graft.

In cases where the access cannot be saved, a catheter placement may be necessary, but valuable information to guide a revision may be gained, making the procedure worthwhile nonetheless.

Endovascular thrombolysis is not simple, and should be attempted only by trained and experienced providers, but it has been shown to reduce unnecessary surgery, provide more timely service and restoration of access, and should be the first resort in patients with clotted access.